Your furnace or wood stove creates gases when heating your home. Installing a flue pipe helps to vent these exhaust gases outside. You may need to replace an old flue that no longer connects properly, or install a new pipe while upgrading your heating system. Whether you are replacing a flue or installing new piping, ensure you have enough pipe to extend from your home to vent gases efficiently. Also, carefully follow all building codes regarding the placement of flues.
Things You'll Need
Sheet metal screws
Fire proof sealant (such as fiberglass rope)
Buy the flue pipe you want to install. Purchase double-wall or triple-wall pipe for a wood stove. This type of pipe has a second or third pipe running along the outside as shielding from the amount of heat that can pass through it. Have enough pipe so it extends higher than any other pipe or vent in the roof.
Run vertical pipe up through the ceiling and roof. Cut a framing hole at least 10 inches in diameter with a jigsaw tool. Check the area where you will install the flue pipe. Pull away insulation or install an insulation shield to keep the area clear around the pipe.
Keep flue pipe as straight as possible for horizontal runs. Install no more than two elbow pipes at 45 degree angles if running the pipe through a chimney stack. Place vent support straps along the pipe every 8 feet if it's more than 25 feet long.
Screw three sheet metal screws to connect the pipe sections, overlapping at least 2inches along the seams. Install a flue collar where the pipe connects to the stove. Apply fireproof sealant. Attach a chimney pot or rain stopper cap on top of the pipe to prevent rain from entering.
Clean flue pipes annually when not in use for wood stoves. Cresote builds up along the inside of the pipe and causes blockage so gases do not vent properly, leading to unwanted back drafts.
Don't let any combustible material lie against the flue pipe for wood stoves. The flue pipe can set material on fire from the intense heat of the gases. Seal all pipe seams to prevent gases from entering your home. Do not run flue pipes out windows or in closets. (You can run flue pipe vertically through a wall.) Avoid wiring and wall studs when creating the framing hole.